Wall anchors can be grouped together in two general types, namely the expanding anchor type, such as the plug and screw type or the expansion bolt type, and the deploying type such as the toggle bolt type.
Anchor of the expanding anchor type are normally easy and economical to manufacture. The plug and screw type is made up of only two elements: a plug and a screw. However, in usage, a predrilled hole much larger than the screw diameter has to be made. Then a plug is inserted in the hole and, finally, a screw is screwed in the plug, thereby expanding the plug and squeezing the exterior wall of the plug onto the surrounding wall of the hole. While plug and screw type anchors insure a fair grip between this anchor and walls formed of plasterboard, the dry wall material is far from creating the optimal holding force.
Similarly, the expansion bolt type is made of two parts: a bolt and a tube-like over sleeve. The over sleeve has a top section resting on the head of the bolt, while the bottom section has a thread section screwed onto the bottom part of the bolt. The middle section of the over sleeve is made up of bent out metal strips. While this type of anchors still relatively easy to manufacture, it is a little more expensive than the plug and screw type. However, these anchors present many drawbacks. First, most inexpensive models require a predrilled hole in which they are inserted. Also, in use, after being inserted in the hole, the bolt is screwed, thereby lifting up the bottom part of the over sleeve. The over sleeve squeezes against the bolt head causes the metal strips of the middle section to bend outwardly against the surrounding wall of the hole, thereby providing the holding grip. While the expansion bolt type insure a fair grip, it is also far from putting in the optimal holding force that can be archived otherwise.
Anchors of the deploying category, such as the toggle bolt type, include more parts and are more expensive to manufacture. These anchors have wings pivot means pivotally attached to the wing and onto a nut adapted to be screwed onto a bolt, along with a biasing means to deploy the wings. The wings are normally in a deployed configuration, but when the toggle bolt is pushed through a hole drilled in the hollow wall, the wings fold in against the bolt to allow passage therethrough. Generally, these anchors require a much larger hole diameter than the bolt diameter. On emerging from the hole, the pivoting wings resume their out-stretched state at a position well displaced from the inner surface of the wall. The user then turns the bolt to move the toggle wings axially toward the inner surface of the wall to tighten the toggle bolt. Aside from their high cost, the toggle bolt type provides the maximum holding force equivalent to the potential holding force that a wall sheeting can provide. However, they usually cannot be removed without losing the wings sections in between the hollow section of the wall.
Against this background, there exist a need for a new and improved wall anchor. It is a general object of the present invention to provide a new and improved wall anchor.